Question

If the velocity of light in glass is $2\times {10}^{8}m/s$, then find its velocity in water, if $n_g=1.5$ and $n_w=4/3$.

• A. $3\times {10}^{8}m/s$
• B. $2.66\times {10}^{8}m/s$
• C. $1.5\times {10}^{5}m/s$
• D. $2.25\times {10}^{8}m/s$

Answer 1

The correct option is D $2.25\times {10}^{8}m/s$

Given,$n_g=1.5,n_w=4/3andvelocityoflightinglassis2\times {10}^{8}m/s.⟹velocityoflightinwateris\frac{v_g\times n_g}{n_w}=\frac{2\times {10}^8\times 1.5}{4/3}=2.25\times {10}^8.$